Ophthalmologic imaging apparatus

Abstract

The present subject matter relates to an ophthalmologic imaging apparatus, which can capture reflex-free retinal images of a subject's eye. The imaging apparatus comprises light sources arranged on an illumination axis. A first shield placed at a distance from a first condenser lens, which is placed in front of a photographic light source on the illumination axis. The first shield has a central opaque portion on which an observation light source is mounted, and an outer pair of coaxial annular transparent regions. A diffuser is placed in front of the observation light source. A second shield has a central opening portion and mounted on the diffuser. The imaging apparatus further comprises a porosity mirror mounted on a porosity tube.

We claim: 
     
       1. An ophthalmologic imaging apparatus to capture retinal images of a subject's eye, the ophthalmologic imaging apparatus comprising:
 a photographic light source arranged on an illumination axis; 
 a first condenser lens placed in front of the photographic light source on the illumination axis; 
 a first shield placed in front of and at a distance from the first condenser lens, wherein the first shield has a central opaque portion and an outer pair of coaxial annular transparent regions; 
 an observation light source mounted on the central opaque portion of the first shield in front of the first shield, wherein the observation light source is arranged on the illumination axis; 
 a diffuser placed in front of the observation light source to diffuse an illumination light beam emitted from the observation light source; 
 a second shield mounted in front of and on the diffuser to receive diffused light from the diffuser, wherein the second shield has a central opening portion bounded by a first opaque ring, an outer pair of coaxial annular opaque portions forming a second opaque ring, and a donut shaped open portion formed between the first opaque ring and the second opaque ring, and wherein the second shield creates an annular illumination pattern from the illumination light beam that passes through the donut shaped open portion; 
 a porosity tube disposed in front of and at a distance from the second shield, wherein the porosity tube is axially aligned along an imaging axis that is perpendicular to the illumination axis; 
 a porosity mirror mounted on the porosity tube, wherein the porosity mirror is at an angle with respect to the imaging axis; and 
 an imaging module aligned along the imaging axis and perpendicular to the illumination axis, wherein the imaging module captures the retinal images of the subject's eye. 
 
     
     
       2. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the observation light source comprises a halogen lamp. 
     
     
       3. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the first shield and the second shield are ring shaped. 
     
     
       4. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the observation light source is mounted at center on the central opaque portion of the first shield along the illumination axis. 
     
     
       5. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the observation light source is mounted between center and periphery of the central opaque portion of the first shield along the illumination axis. 
     
     
       6. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the ophthalmologic imaging apparatus comprises a transparent plate having a black dot absorber and the transparent plate is placed between the second shield and the porosity tube. 
     
     
       7. The ophthalmologic imaging apparatus as claimed in  claim 6 , wherein the ophthalmologic imaging apparatus comprises a second condenser lens placed between the transparent plate- and the second shield. 
     
     
       8. The ophthalmologic imaging apparatus as claimed in  claim 6 , wherein the ophthalmologic imaging apparatus comprises at least one projection lens placed between the porosity tube and the transparent plate. 
     
     
       9. The ophthalmologic imaging apparatus as claimed in  claim 1 , wherein the observation light source comprises plurality of LEDs, and the ophthalmologic imaging apparatus comprises a control circuit control the operation of the plurality of LEDs. 
     
     
       10. The ophthalmologic imaging apparatus as claimed in  claim 9 , wherein the observation light source comprises a rotatable turret assembly mounted with the plurality of LED's of one or more predefined wavelengths, and a rotational axis of the rotatable turret assembly is parallel to the illumination axis and separated from the illumination axis is such a way so that the center of each of the LEDs is aligned on the illumination axis when the rotatable turret assembly is rotated to select one or more LEDs of the plurality of LEDs operating a specific wavelength. 
     
     
       11. The ophthalmologic imaging apparatus as claimed in  claim 9 , wherein the plurality of LEDs are arranged on the central opaque portion of the first shield, and each LED of the plurality of LEDs operate at a predefined wavelength of light. 
     
     
       12. The ophthalmologic imaging apparatus as claimed in  claim 11  wherein one or more of the plurality of LEDs are white LEDs to operate the ophthalmologic imaging apparatus in a mydriatic mode. 
     
     
       13. The ophthalmologic imaging apparatus as claimed in  claim 11 , wherein one or more of the plurality of LEDs are infrared LEDs to operate the ophthalmologic imaging apparatus in a non-mydriatic mode. 
     
     
       14. The ophthalmologic imaging apparatus as claimed in  claim 13 , wherein the infrared LEDs operate at a wavelength of light greater than 700 nm.